Preliminary Purchase Price Allocation - Distra (Detail) (USD $) In Thousands, unless otherwise specified				1 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Sep. 18, 2012 Distra Pty Ltd	Sep. 18, 2012 Distra Pty Ltd Software	Sep. 18, 2012 Distra Pty Ltd Customer relationships
Business Acquisition [Line Items]
Total current assets acquired			$ 1,857
Goodwill	625,990	501,141	22,139
Amortizable intangible assets				18,802	6,200
Deferred income taxes			4,075
Other noncurrent assets			96
Total assets acquired			53,169
Current liabilities acquired			3,419
Net assets acquired			$ 49,750
Weighted-Average useful lives				7 years	10 years